Semi-permanent memory



Feb' 8, 1966 cHxA Y. HsuEH ET AL 3,234,529

SEMI-PERMANENT MEMORY Filed Oct. 23, 1962 ,1

United States Patent O 3-,234,529 SEM-'I-PERNANENT' MEMORY Chla Y. Hsueh, Levittown, Pa., and David E. Williams, Stratford, NJ., assignors to Radio Corporation of America, a corporation. of Delaware Filed O ct. 23, 1962, Ser. No. 232,404 6 Claims. (Cl. 340-174).

This inventionV relates to So-called Semi-permanent readonly memories of the type Wherein any selected information word may be read out electronically, and wherein the words stored in the memory arev determine-d by the physical con-fivurations of m'anually interchange'able members.

There are applications in electronic data processing apparatus for Vboth random access memories and read-only memories. A read-only memory is one wherein the Storage of information is relative-ly fixedv 'by the mechanical or physical configuration or construction of the memory, and wherein the stored information canbe electrically or electronica-lly read out as freq-uently asis desired without destroying the stored information; Punche-dl cards are an example of a read-only memory wherein each card is employed for the storage of one or more words. Punched cards are usually read one card at a time in time sequence. It is `desirable t-o have 'a read-only memory capable of storing a large number of words, and having means for electronically addressing any selected one of the word locations for reading out the selected stored word. It is .als-o desirable to have an electronically address/able readonly memory permitting of the convenient manual substitution of Store-dl information words in the memory. It is additionally desirable in many instances to have a readonly memoryV capable of storing information in tertiary form wherein each bit of each stored information word represents a a or a 0.

It is a -general object of 'this invention to provide an limproved fixed 'or read-only memory wherein the storage of tertiary digital information is determine-d by the configuration of conductors linking apertures in a plurality of magnetic cores.

It is another object to provide an improved read-only memory construction which permits. the changing of stored tertiary digital information by S-ubstitut-ing mechanical members -determining the store-d information.

It is a further object to provide an improved read-only memory wherein stored tertiary digital information is determined by the presence and location of holes punched in a Sheet having a printed circuitthereon.

It is yet another object to provide an improved' readonly memory for the storage and reading of tertiary information, that is,V onewherein each bit of information is represente'd by one of three States or values.

According to an example of the invention, there is provided a pluralityV of two-apertured magnetic cores,4 there being as many cores as thereV are information bits in each of the words to be stored in the memory. The magnetic cores are each constructed of an E-shape magnetic memher having a removable magnetic bar located across the central and side legs to define a magnetic core having two apertures. The primary winding conductors are conductors that are printed in a ladder-pattern on an insulating Sheet arranged to be inserted on the E-cores so that the conductors go through the apertures of' the cores when the bars are in place. T-he printed winding sheets and the conductors thereon are punched out at select'ive points to 'determine the information bits of the stored word on each sheet. Words of stored information can be changed :by merely Substituting one punched primary winding Sheet for another. Information is read from the memory by energizing a selected one of the conductors on a printed ice sheet 'and sensing the signals inducedonsecondary` windings on each magnetic core.

The ladder-pattern printed primary conduotor onan insulatingV Sheet is punched (for the storage of' tertiary information) in such a- Way th-atar-emaining conductive path throughone of the aperturesofa core provides forv the storage of aa conductive path. through the other aper-ture ofar core; provides for the storage of a and conductive paths through both -apertures of acore provide for the-stor'age of a 0.4

These and other objects and advantages of the invenf tion will be apparent to those skilledi in the, art from the' following'more detailed; description taken in. conjunctionV with the appended; drawing, wherein:

FIGURE 1 is: a perspective. view of asemi-permanentread-only memory constructe-d according to, the invention wherein there is illustrated theV storage of one. threef bit Word wherein each bit. is in tertiary form representing a +,S, a dtor a (50.974

FIGURE 2v is, a representation of: asingle core whichwill -bereferred toin describing theoperation of the memory of FIGURE 1; and

FIGURE 3 is a block diagram. of afixed memory inclu-ding the construction of- FIGURE 1 and including associated electronic circuits.

ReferenceV will now be made in greater deta-il to'FIG- URE. 1 of` the drawing which includes three magnetic cores 10; 12 `and 14 each having E-shaped members with av central leg 1-6 and twoend legs- 1-8 and 20. A magnetic 'bar 22 is postione-d at the ends. of the legs of eachy E core to cooperateV with the E core to provide a magnetic core having two fapertures 24 .and 26. 'I'Ihe E Cores and -bars are preferably constructed. of a ferrite magnetic material such as is commonly employed for pulse transformers. As described hereinafter, the memory does not rely Iupon a Square loop hysteresis characteristic for storing information. Instead, the cores vare used in the m'anner of a transformer core, rather than in the manner of a memory 'core having high retentivity in two. magnetic States. Preferably, the cores have a linear magnetizat-ion ch'aracteristic. i

Each word of information stored in the memoryis determined by the configuration of a primary winding conductor 39 which provides a conductive path extending through the aperture 24 of core 10 forthe storage ofV a extends through both apertures' 24 and 26 of' core 12 for the. storage of a. 0;r and extends through aperture 26 of core 14' for the storage of a While FIGURE 1 shows only one primary winding conductor for the storage of one word having three tertiary-bits, it will be understood that a memory according to theinvention will normally' 'have' a large number (-suchv as sixty-four) of primary winding conductors 30- for the purpose ofstoring a correspon-ding number of words.

Each primary windingcon-ductor 30 is constructedas a printed winding having a ladder pattern ona Sheet 346 of insulating` materialv Su-ch as the plastic Mylar Each primary winding Sheet' 361 is provided with. apertures 38' a-d'apted to fit over the central legs 16` of the' respective magnetic cores and to have sides which `fit. within. the side legs 18 and 20 of'each core. Each ladder-pa'ttern printed primary windingconductor 30,v includes` side, con-. ductors 40- and 42: extendingl through the respective apertures. 24V and 26. of the-cores, and transverse conductors 44: extending between the sideV conductors and located between the successive cores.

Each -ins-ul'ating Sheet 36 with.V a ladd'er-pattern printed; primary winding thereon is select-ively punched for the storage of a desired word prior lto a-srsembly of the insulating s'heet'in the. cores. The conductor 42 is punched out at 46 leaving the conductor 40 threaded-thr-ough the aperture 24' 'for' the Storage of a 'at the core 10.

The |conductor 40 -is punched out at 48 leaving the conductor 42 passing through the aper-t-ure 2-6 in core 14 for the storage of a at the core 14. The conductors 40 and 42 are unpunched at the' core 12 'so that they both conduct current through the apertures 24 and 26 of the c-ore 12 for the storage of a at the core 12. Each of the conductors 30 has -two terminal-s 50 and 52 for connection to electronic circuits 'as will be described.

The Icentral leg 16 of each of the cores 10, 12 and 14 has wound therearound a multi-turn secondary winding 54. The 'secondary windings 54 are' preferably printed windings having a pancake -configuration, t-he wind- -ing-s being 'printed on a secondary wind-ing insulating sheet 56 having the same general configuration as the primary winding insulating sheets 36.

FIGURE 2 will now be referred to -in descri'bing the operation of each of the magnetic cores in the art-angement of FIGURE'I. A primary winding conductor V40 carrying a current pulse goingint-o the paper causes a change in magnetic flux around the aperture 24 in the direction represented by the arrow 58. This change, by transformer action, ind-uces a signal in the secondary winding 54 which appears Vat .the output terminal 59 as a signal pulse of one polarity which may represent a stored 1. An output signal of 'the opposite polarity representing a stored is provided when the primary winding conductor 42 of another word is energized by a current pulse going into 'the paper 'through aperture 26 to prod'uce flux in the directi-on represented 'by the arrow 60. There is no output signal, representing a stored 0, provided at the output 59 of the secondary coil 54 when current flows sirnultaneously in both conductors 40' and 42' through both apertures 24 and 26 because the fluxes 58 and 60 cancel each -other in the central leg 16 linked by the secondary coil 56.

The signals, described above, are ind'uced -in the secondary winding 54 during the leading edge of the interrogation pulse applied to a primary winding conductor 40.. Thetrailing edge of each interrogation pulse cause's the ind-uction of an opposite-polarity signal in the secondary winding. Solely -the signals due to the leading edge of the interrogation pulse (or the trailing edge) are sensed by strobing the sense amplifier (FIG- URE- 3) in the customary manner.

FIGURES illustrates a memory system including a plurality of cores including those labeled 10, 12 .and 14, all the cores 'being linked by conductor-s 30 each of which defines one of a plurality of words stored in the memory. The terminals 50 'and 52 of each primary winding conductor 30 are connected to selection drivers 64 and selection switches 66, respectively. The driver-s 64 and switches 66 are operated under the control of a decoder 68 in response to signals on input lead 70 which identifies the particular word desired to 'be read out from the' read-only memory. t The drivers 64, -switches 66 and decoder 68 are conventi-onal known circuits for the selection of one of a number of conductors or word lines in a memory. The 'secondary coilr4 wound on each of the cores is coupled to Va respective sense amplifier 72. The several sense' amplifiers each provide one digit of the interrogate'd word on the output leads labeled 20, 21, 22 and 2B.

T hus, the operation of the read-only memory is 'such a that every 'time an interrogation pulse is applied'to' a selected one of -the primary winding conductors 30, the information bits available Oat 'the `outputs of the sen'se amplifiers 72 represent the information 'bits of 'the'selected w-ord` storedpin the memory by the configuration of the selected primary winding. g w The insulating sheets` 36 with ladder-pattern printed windings 30 thereon, may be'supplied unpunched to 'a memory user. l The user can punch theV sheets to provide for 'the'storageof a-corresponding number of information Words in a manner analagous to the usual punching of information on paper cards. The user can, by removing the bars 22 from the E cores, insert the punched secondary sheets in the cores. Thereafter, the user can conveniently change a word or words stored in the memory by vsubstituting one or more punched primary sheets for'one or more punched primary sheets in the memory.

What is claimed is:

1. A memory |construction comprising a plurality of magnetic cores each having two aper- 'tures with la central magnetic leg therebetween,

a plurality of primary windings each extending through apertures of all of said cores, a primary winding eX-tending through solely -one aperture of a core to store a extending 'solely through the other aperture of a core to store a andextending in Iparallel paths through both of the apertures of a core to store a 0, and

a secondary winding wound around the central leg of each of said magnetic cores.

2. A memory construction for the storage of m words each having n tertiary bits, comprising n magnetic cores each having two apertures with a central magnetic leg there'between,

m primary windings extending through apertures of all of said cores, a primary winding extending through solely 'one aperture of a core to store a extending solely through the other aperture of a |core to store a andextending in parallel paths through both of the apertures of a core to store a 0, and

a secondary winding wound around the central leg of each of said magnetic cores.

3. A Semi-Permanent memory construction for the storage of m words each having n tertiary bits, comprising n magnetic cores each having two apertures with a central magnetic leg therebetween,

m primary windings extending through apertures of all of said cores, a primary winding extending through solely one aperture of a core to store a extending solely through the other aperture of a core to store a -jf and extending in parallel paths through both of the apertures of acore to store a 0,

a secondary winding wound around the central leg of each of said magnetic cores,

means to apply an interrogation pulse through any 'selected one of said primary windings, and

means to sense the signal induced in each of said secondary windings `as a a or a "0 depending on the location of the iuterrogated primary winding with relation to the particular core.

4. A memory construction for the storage of m words each having n tertiary bits, comprising h m insulating primary sheets each having n apertures therein and each having a ladder-pattern printed primary winding thereon wherein first and second side conductors extend on the two 'respective sides of the apertures and wherein cross conductors connect the side conductors between the apertures, a portion of the first side conductor near an aperture being punched out for the storage of a a portion of the second side conductor near anv aperture being punched out for the storage of a and the first and second side conductors near an aperture being unpunched for the storage of a 0,

n secondary windings,

n magnetic cores each having an E-shaped member,

each having a central leg through corresponding apertures in all of said primary sheets and through one secondary winding, and each having side legs outside of one of said secondary windings, and

each of said cores having an individual magnetic bar bridged across the ends of the central and side legs of each of said E-shaped members.

5. A semi-perrnanent construction for the storage of 75 m words each having n tertiary bits, comprising m insulating primary sheets each having n apertures therein and each having a ladder-pattern printed primary Winding thereon wherein said pattern includes first and second side conductors corresponding to the ladder legs extend on the two respective sides of the apertures and wherein cross conductors correspond ing to the ladder bars of the pattern connect the side conductors between the apertures, a portion of the first side conductor near an aperture being punched out for the storage of a a portion of the second side conductor near an aperture being punched out for the storage of a and the first and second side conductors near an aperture being unpunched for the storage of a 0,

an insulating secondary sheet having n apertures therein each surrounded by a secondary Winding,

n magnetic cores each having an E-shaped member with a central leg through corresponding apertures in all of said primary sheets and through one aperture of said secondary sheet, and having side legs, and

a magnetic bar bridged across the ends of the central and side legs of each of said E-shaped members.

6. A semi-permanent memory construction for the storage of m Words each having n tertiary bits, comprising m nsulating primary sheets each having n apertures therein and each having a ladder-pattern printed pri mary winding thereon wherein first and second side conductors extend on the two respective sides of the apertures and wherein cross conductors connect the side conductors between the apertures, a portion of the first side conductor near an aperture being punched out for the storage of a a portion of the second side conductor near an aperture being punched out for the storage of a and the first and second side conductors near an aperture being unpunched for the storage of a 0,

an insulating secondary sheet having n apertures therein each surrounded by a multi-turn pancake printed secondary Winding,

n E-shaped magnetic cores each having a central leg extending through corresponding apertures in all of said primary sheets and extending through one aperture of said secondary sheet, and having side legs extending outside said primary and secondary sheets,

a magnetic bar bridge across the ends of the central and side legs of each of said E-shaped cores,

means to apply an interrogation pulse through any selected one of said primary windings, and

means to sense the signal induced in each of said secondary windings as a a or a 0 depending on the effective configuration of the interrogated primary Winding.

References Cited by the Examiner UNITED STATES PATENTS 2,778,005 1/1957 Allen 340 174 2,963,687 12/1960 Briggs 340-174 3,044,044 7/1962 Lee 340-174 IRVING L. sRAGoW, Primary Examz'ner. 

1. A MEMORY CONSTRUCTION COMPRISING A PLURALITY OF MAGNETIC CORES EACH HAVING TWO APERTURES WITH A CENTRAL MAGNETIC LEG THEREBETWEEN, A PLURALITY OF PRIMARY WINDINGS EACH EXTENDING THROUGH APERTURES OF ALL OF SAID CORES, A PRIMARY WINDING EXTENDING THROUGH SOLELY ONE APERTURE OF A CORE TO STORE A "+," EXTENDING SOLELY THROUGH THE OTHER APERTURE OF A CORE TO STORE A "-," AND EXTENDING IN PARALLEL PATHS THROUGH BOTH OF THE APERTURES OF A CORE TO STORE A "O," AND A SECONDARY WINDING WOUND AROUND THE CENTRAL LEG OF EACH OF SAID MAGNETIC CORES. 